Depending on the crowd, he could have been booed for trying something like that. You might do that when you're up a set and 5-0 but even then it's still insulting to your opponent and to the people watching. And about the shot: He looked like a complete fool. The shot wasn't good at all, too soft and right in Haas' racket. When you're doing something stupid like that, at least try to make it a winner (or UE), what the hell was this supposed to be?